An image forming apparatus such as a multi-function peripheral or a laser printer includes a fixing device for fixing a toner image to a sheet. The fixing device fixes a toner image transferred onto a sheet to the sheet by applying heat generated by a heater to the sheet via a fixing belt, for example. In this way, an image or a character can be printed on the sheet.
In such a fixing device, a pressing roller is pressed via the fixing belt towards a pressing pad arranged at the inner side of the fixing belt, thereby forming a nip through which a sheet passes between the fixing belt and the pressing roller. Therefore, at the time the sheet passes through the nip, as the fixing belt and the pressing roller rotate, an inner peripheral surface of the fixing belt slides with respect to the pressing pad. For this reason, a lubricant such as silicone oil is applied to the inner peripheral surface of the fixing belt. In some cases, a sheet with low frictional resistance is arranged between the fixing belt and the pressing pad. In this way, the frictional resistance between the fixing belt and the pressing pad is reduced.
However, since silicone oil is reduced due to leakage from an end of the fixing belt, sliding property of the fixing belt and the pressing pad is weakened as the device operates. Therefore, various technologies are proposed to suppress reduction in the sliding property of the fixing belt and the pressing pad. In such a technology, the lubricant is applied to the surface of the fixing belt by supporting a lubricant supply member such as a felt impregnated by the lubricant in such a manner that the lubricant supply member slides on the surface of the rotating fixing belt.